Cholesterol is the steroid alcohol and type of lipid. Steroid alcohol or sterols are a type of steroid and steroids are type of lipids. It is essential for human life.
Animals including human can synthesize cholesterol mainly in liver and intestine. It take place in endoplasmic reticulum with the starting molecule Acetyl-CoA. Human body can synthesize all the required cholesterol.
As animals can produce cholesterol, it can be found in food sources from animals such as egg yolk and meat. As plants cannot synthesize cholesterol, it is not present in food of plants origin.
Cholesterol is present in all cells of body. It is found in plasma membrane of the cells and helps to maintain the membrane fluidity. It is also used for the synthesis of several hormones in the body such as steroid hormones (corticosteroid) and bile acid.
The viruses that lie dormant in host cells until ready to multiply use : Lysogenic cycle During the lysogenic cycle the virus do not kill the host. It integrate it's dna with the host's so it could lie dormant until it ready to multiply
